Physiological responses of Populus euphratica Oliv. to groundwater table variations in the lower reaches of Heihe River, Northwest China

Riparian vegetation in the lower reaches of Heihe River serves important ecological functions. However, the riparian ecosystems have been constantly deteriorating in the past 30 years simply due to water interception for oasis agricultural irrigation in the middle reaches of the river. This study pays a particular attention to Populus eu- phratica Oily. forest because it is a dominant component of the riparian ecosystem in the lower reaches of Heihe River where the depth of groundwater table is the controlling factor in sustaining riparian ecosystems. To reveal leaf-related physiological responses of Populus euphratica Oliv. forest to groundwater table variations, we analyzed the relationships between the depth of groundwater table （DG） and three leaf-related parameters, i.e. leaf stomatal density （SD）, specific leaf area （SLA）, and stable carbon isotopic composition （6~SC）. Our results show that the relationship between DG and leaf SD is a bi-mode one shaped by both salt stress and water stress. That is, salt stress appeared in shallow groundwater conditions and water stress happened in deep groundwater conditions, and the thin layer around 2.7 m of DG is a stress-free layer. Leaf SD fluctuated according to the DG variation, first de- creased with increasing DG, then increased at depths ranging 2.7-3.7 m, and after a relatively stable plateau of SD at depths ranging 3.7-5.2 m, decreased again with increasing DG. Our results also show that SLA decreased ex- ponentially with increasing DG and foliar 6130 values are also strongly dependent on DG, further demonstrating that these two parameters are sensitive indicators of water stress. The exponential curve suggests that SLA is more sensitive to DG when groundwater table is shallow and 3 m seems to be a threshold beyond which SLA becomes less sensitive to DG. Foliar 613C becomes more sensitive when the groundwater table is deep and 7 m seems to be a threshold below which the 6130 signature becomes more sensitive to DG. These findings should be helpful in monitoring the growth and development of Populus euphratica Oliv. forests and also in providing protection measures （i.e. DG related） for Heihe River riparian forests.

Effect of Irrigation on Groundwater Dynamic Change in the Typical Irrigated Area of Qinghai Province

Under the influence of the natural and human factors, water table of irri- gated area Changes frequently, but it is mainly affected by irrigation water infiltration replenishment during the irrigation. 5 groundwater observation wells were constructed in experimental plot of the Daxia irrigated area to carry out the experiment of the effect of irrigation on groundwater dynamic change in this research. The results showed that the groundwater stage dynarnic change rule of spring and seedling irri- gation stage in the typical plot was fit to the hydrological geology condition of grade- I terrace of Huangshui river valley. On the whole, lateral canal water direction formed a line effect. The No. 1 and No. 2 observation well were the closest to the lateral canal, which received more supplies, and the water level was the highest; the No, 3 observation well took the second place; The No. 4 and No. 5 observation well accepted least supplies, and the water level was the lowest. The rangeability of water table of spring irrigation period was significantly higher than that of seedling irrigation period, this is mainly due to the difference value of intake water volume and drainage water volume of spring irrigation phase was significantly higher than the seedling irrigation phase.

Numerical simulation of groundwater and early warnings from the simulated dynamic evolution trend in the plain area of Shenyang,Liaoning Province(P.R. China)

Groundwater level is the most direct factor reflecting whether groundwater is in a virtuous cycle. It is the most important benchmark for deciding whether a balance can be struck between groundwater discharge and recharge and whether groundwater exploitation will trigger problems pertinent to environment, ecology and environmental geology. According to the borehole and long-term monitoring wells data in the plain area of Shenyang, a numerical groundwater model is established and used to identify and verify the hydrogeological parameters and balanced items of groundwater. Then the concept of red line levels, the control levels of groundwater is proposed, the dynamic evolution trend of groundwater under different scenarios is analyzed and predicted and groundwater alerts are given when groundwater tables are not between the lower limit and the upper limit. Results indicated:(1) The results of identification and verification period fitted well, and the calculation accuracy of balanced items was high;(2) with the implementation of shutting wells, groundwater levels in urban areas of Shenyang would exceed the upper limit water level after 2020 and incur some secondary disasters;(3) under the recommended scenario of water resources allocation, early-warnings for groundwater tables outside the range would occur in the year of 2020, 2023, 2025 respectively for successive wet, normal and dry years. It was imperative to reopen some groundwater sources and enhance real-time supervision and early-warning to prevent the occurrence of potential problems.

A review on investigation of water-preserved coal mining in western China

Yushenfu mining area is located in an ecological fragile area in western China, the coal seam of which is the Jurassic Ysn'an Foirnalion. The Jurassic Yan'an Formation con tains five minable coal seams, the top layer of which is thick, covered by shallow overburden and located under aquifers. Therefore, the mining induced water flowing fractured zone can easily extend to the aquifers of both the Quaternary Sarahu and Jurassic Zhiluo Formation. This would result in a series of negative hydrological and ecological effects, including groundwater leakage, groundwater lowering, furtherly causing surface vegetation withering and dying, surface water body reduction, spring drying out, and water flow of river being decreased substantially. To solve these environmental problems, several technologies have been carried out by Chinese scientists, one of which is water-preserved coal mining. This paper presents a review of the origin, definition and development of water-preserved coal mining, and its applications in Yushenfu mining area. The applicable conditions, research contents, research methodology, and technical foundation of water-preserved coal mining are addressed in this paper. The future research focuses regarding water-preserved coal mining in China are also discussed in this paper. Its results serve as a guide for selecting the methods to be preferred for mining in case the geological conditions, roof overburden structure and coal mining process are similar to Yushenfu mining area.

Changes in regeneration and leaf traits of Rhododendron campanulatum along a treeline ecotone in central Nepal

Changes in population structure and plant functional traits across environmental gradient in the near natural treeline is a critical determinant of environmental changes in treelines. In this study we analyzed population characteristics and leaf traits of Rhododendron campanulatum across treeline ecotone in a trans-Himalayan region of Mustang district in central Nepal. Along 4 vertical transects, a total of 72 quadrats(5 m × 5 m)-34 above Betula utilis treeline and 38 below treeline-were sampled to analyze the population structure, regeneration,specific leaf area(SLA) and leaf-stem relationship of R. campanulatum. Our results showed that the regeneration of R. campanulatum was fairly good in both habitats, as evident from density-diameter curve.The species showed type Ⅲ survivorship curve in both habitats with the highest mortality during early stage of life. However, the seedling density and mortality was higher below treeline than above treeline. Canopy cover and basal cover were found to be the major factors affecting regeneration, as indicated by higher number of juveniles in relatively open areas above treeline. The total leaf area increased(p <0.001) with stem cross-section area in both habitats. However, the SLA was higher below treeline(55 cm^2/g) than above(47 cm^2/g)(p < 0.001);it also increased with the canopy cover of trees(R^2 =0.59, p <0.001) below the treeline. In conclusion,high density of juvenile, low mortality of seedlings,and low SLA above treeline indicated that the species has successfully adapted in climatically stressful alpine habitat with potential to expand upward.

地理空间数据等积全球格网多模式三维扩展方法

全球离散格网系统是新型地理空间数据组织框架,等面积格网由于在采样和空间分析方面的独特优势而备受关注,但相关研究囿于地球表面,缺乏扩展至三维广域空间的一般方法。本文首先提出将等积球面格网系统扩展为球体格网系统的多种剖分模式,并实现其统一数学描述和详细数学证明;然后引入体积和紧致度指标定量评价不同剖分模式的体元性质,并与球体退化八叉树格网(SDOG)、大圆弧八叉树格网(SGOG)作对比;最后初步探索了本文方法的应用案例,讨论了不同应用需求下选择剖分模式的原则。对比试验结果表明,退化剖分的体元各项指标均优于规则剖分,等体积和退化剖分的体积性质优于SDOG,紧致度性质优于SGOG。本文多剖分模式三维扩展方法不仅符合国际标准等体积的要求,而且兼顾常规剖分设计选项,为不同应用需求提供了参考依据。

软土超大面积基坑群工程安全与环境控制设计与实践

软土地区超大面积基坑群工程安全和环境影响控制问题突出,成为城市建设中的难题。以上海地区规模最大、最复杂的基坑群工程之一的西岸传媒港与上海梦中心项目为背景,基坑支护设计跳出传统的构件设计框架,从总体与细节上对基坑群工程进行整体把控。在综合考虑不同地块的开发进度需求、多地块叠加作用下敏感环境保护等问题的基础上,合理化基坑分区与实施流程。提出了复杂多约束条件下基坑群支护体系设计和以运营地铁为保护对象的敏感环境变形控制成套技术,以及安全与经济并举的基坑群承压水控制对策。上述措施解决了软土地区超大面积基坑群工程一系列技术难题,确保了基坑施工过程中周边环境安全,同时兼顾了工期需求。

4个葡萄鲜食品种在四川成都地区的栽培表现

【目的】对‘红阳光’‘黑阳光’‘浪漫红颜’‘妮娜皇后’4个葡萄品种在四川省成都地区引种栽培的物候期、果实经济性状和抗病性等进行调查研究,筛选出适宜成都市气候特点的鲜食葡萄新品种。【方法】2022年3月—11月记录每个品种物候期、植物学性状、果实经济性状以及抗病性调查。【结果】4个品种的物候期较为接近,生长势都很强,经济性状很优异‘红阳光’‘黑阳光’易感病,‘妮娜皇后’‘浪漫红颜’抗病性较强。【结论】‘浪漫红颜’和‘妮娜皇后’的综合性状表现优异,可以在成都地区推广种植;‘红阳光’和‘黑阳光’不建议在成都地区大量种植。

“镇—村”二级主体功能区细分思路与实践——以湖北省枝江市为例

主体功能区在国土空间开发保护格局中具有战略性、基础性和约束性作用,是国土空间实现精准施策、精细管控的重要抓手,新时期各地对主体功能区的细分进行了大量的探索。本文以湖北省枝江市为例,通过自上而下和自下而上结合的方式,构建“镇—村”二级主体功能区评价指标体系,结合定量的功能空间比例,细分了“镇(街道)—村(社区)”二级主体功能区,并构建了功能与指标传导和用途与项目落实的路径,以期为县级城市主体功能区细化及高水平治理提供借鉴。

奎屯垦区26个鲜食葡萄品种果实品质的综合评价

为了筛选适宜新疆奎屯垦区种植的鲜食葡萄品种,对引进的26个葡萄品种的穗质量、可溶性固形物、总酸、色差值等18个品质指标和3个感官指标进行评价分析,并利用主成分分析法建立综合评价模型。结果表明,各品种间穗质量变异系数为26.39%,可溶性固形物差异较小,果皮颜色丰富,饱和度变异系数达到82.92%;感官分析评价表明,‘贵妃玫瑰’‘阳光玫瑰’‘奇妙无核’3个品种更受欢迎;相关性分析表明,各指标之间存在一定的相关性,可溶性固形物与C、L、b、△E均呈显著负相关;主成分分析显示,‘醉金香’‘户太八号’‘红地球’的综合果实品质相对较好,适宜在新疆奎屯垦区推广种植。

东部高潜水位矿区离层注浆减沉可行性分析

潘谢矿区受多煤层重复采动影响,地面沉降等环境地质问题严重,开展离层注浆减沉技术研究,有利于释放煤炭资源,减轻地面沉降的危害,对高潜水位矿区的绿色低碳发展意义重大。以潘谢矿区8对生产矿井作为研究对象,结合煤矿水文地质、开采技术条件、采掘工程现状等情况,建立了特殊条件下的注浆工作面甄选原则。采用3DEC软件对某矿1616(3)工作面13-1煤回采结束后未注浆和不同注采比情况下的注浆效果进行预测,最终作出特殊条件下淮南矿区离层注浆减沉的可行性分析。结果表明:①研究区内110个工作面甄选结果显示有6个工作面符合注浆条件,离层注浆技术在潘谢矿区可行;②模型预测结果显示:沉降曲线于中心对称,地表下沉量最大值位于采空区中部;随着工作面推进,地表下沉量增大,且沉降曲线极大值的位置向工作面推进方向移动;③当注采比大于60%时,地表最大沉降量从2000 mm减小到400 mm以下,减小了80%以上,表明注浆可有效缓解地表沉降。

基于PAI平台的电力大数据价值挖掘模式的探索与实践

随着电网信息化水平的不断提升,数据作为信息的载体呈现爆炸性增长。传统电力数据挖掘模式在数据获取、建模、分析和模型评估等方面自动化集成水平低,各阶段工作衔接不紧密,同时大部分模型构建复杂,耗时较多,与国家电网公司要求的高效、精准洞察业务价值目标存在一定的差距。基于电力云平台和全业务统一数据中心的建设完成,提出了一种集数据获取、模型构建、分析评估为一体的数据挖掘新模式,通过简化实验性数据获取流程,降低模型构建难度,有效提升电力大数据价值挖掘的速度,全面服务公司业务价值提炼工作。

亭子口灌区水利工程数字展厅功能探究

亭子口灌区水利工程作为国家的一项重大水利项目,积极探索了水利数字化建设工作,其数字展厅作为对外宣传和展示的重要载体,将物理动态沙盘、BIM与GIS结合的决策驾驶指挥舱、智能建造管理平台等融为一体用于该工程的建设,取得了非常好的效果。阐述了以亭子口灌区水利工程为例对整个数字展厅的打造及功能设计进行的探索与研究,旨在为类似工程数字展厅建设提供参考和借鉴。

强震区软弱土层差异厚度下单桩动力响应振动台试验

为探明不同类型地震波作用下软弱土层差异厚度对单桩动力响应特性的影响,采用振动台试验,开展了不同软弱土层厚度变化下桩基础的加速度、水平位移、弯矩动力响应变化特性及桩基损伤分析。试验结果表明:地震波作用下,桩周土体的约束作用受软弱土层厚度的影响显著。桩身加速度在软弱土层中的放大效果最为显著,桩顶加速度放大系数与软弱土层厚度呈正相关;桩顶水平位移在软弱土层厚度最大时达到最大;桩身弯矩最大值出现在软弱土层中,随其厚度增大而增大。不同土层厚度下,桩身弯矩最大值均小于抗弯能力设计值,桩基完整性较好。桩基础抗震设计计算时,应重点加强桩基础在软弱土层中的抗震能力,并选择多种地震波进行抗震验算。

基于KingView的十字工作台虚拟PLC实验平台设计

为弥补高校资金有限、十字工作台台套数不足的缺憾,从十字工作台的驱动系统和FX3U PLC定位控制方法出发,运用组态王的仿真技术开发了十字工作台虚拟PLC实验平台,分别从通信设置、画面设计、变量定义和命令语言、脉冲当量和细分设置的模拟与仿真等方面进行了详细的介绍,并运用“双片叶”实验,从4种不同情形下的图案的形状、大小、均匀度以及绘图时长等几个方面证实了该十字工作台虚拟PLC实验平台的可行性和实用性。

强震区近断层桥梁桩基础时程响应振动台试验

为进一步探明强震区近断层桥梁桩基础动力时程响应规律,依托海文大桥实际工程,采用1g振动台模型试验,开展0.35g不同类型地震波作用下,无断层及近断层桥梁桩基础加速度、桩顶相对位移、桩身弯矩动力时程响应及其差异与桩基损伤分析。结果表明:受发震断层及断层破碎带散体材料特性等因素的影响,改变了地基土半无限体性质。由于断层破碎带相较于地基土结构性较差,强度较弱,断层破碎带–地基土相互作用对地震波的放大效应较为明显,导致近断层桥梁桩基础的动力响应特征相较于无断层桩基础更为明显,其桩基加速度峰值、桩顶相对位移及桩身弯矩均较大,且加速度峰值出现时刻早于无断层桩基,平均提前0.44~3.18 s,近断层桩基础的桩顶加速度及桩顶相对位移时程响应在10 s左右振幅较大,位移响应在30 s作用开始衰减,此时段内桩基础动力响应特征最为明显。近断层桩基础桩身弯矩最大值均未超过其抗弯极限承载能力,且有20.36%~28.41%的抗弯承载能力富余,且基频没有发生变化,表明海文大桥桩基础满足抗震设防烈度Ⅷ度的要求。综上所述,近断层桥梁桩基础抗震设计时,应考虑地震波频谱特性的差异对桩基础产生的影响,根据多种类型地震波对近断层桥梁桩基础进行抗震分析与验算,并进一步增强近断层桩基础的抗震能力。

塞罕坝地区云杉立木材积表的研究

森林蓄积是森林生物量的主要组成部分,是各类森林资源监测的重要指标,为了准确估算塞罕坝地区云杉蓄积量,指导该地区云杉林的经营,本研究基于塞罕坝地区云杉样木实测数据,建立了该地区云杉林的二元材积模型和一元材积模型,根据以上2个模型构建了塞罕坝地区云杉林的二元立木材积表和一元立木材积表,并分析了经营措施对云杉林高径比的影响,比较了2个立木材积表的适用性,得出以下结论:(1)云杉林的高径比随抚育强度的增加而降低,随密度的增加而增加;(2)塞罕坝云杉林最优的二元、一元材积模型分别为V=0.00008506D 1.969 H 0.684,V=0.000140D 2.400;(3)应用t检验证明在塞罕坝地区,以上2个材积模型建立的材积表均有良好的适用性;(4)一元材积表计算出的未抚育林分蓄积量比二元材积表偏低,而抚育后计算出的云杉林蓄积量则略高于二元材积表的计算结果。

230客位小水线面客船总体设计

考虑到小水线面船型在型线及布置上较难满足SOLAS2020破舱稳性的要求,结合230客位小水线面客船设计任务,对小水线面支柱体宽度进行多方案阻力性能、耐波性及稳性计算分析,结果表明,采用增加舱室水密分舱数和降低重心的方式可使得概率破舱指数提高13.2%,再通过增加小水线面支柱体的宽度,可使得该指数进一步提高16.6%,满足SOLAS2020的稳性(特别是破舱稳性)要求。小水线面客船在船型设计开发时需要特别注意总布置设计、型线设计和破舱稳性之间的综合分析。

国家重点生态功能区与毗邻城市高质量发展水平测度及差异研究

以陕西省重点生态功能区及其毗邻的重点开发区作为研究区域,从人口、生态、经济和社会四个系统构建高质量发展水平测度指标体系,运用CRITIC熵权法、引力模型、趋势移动平均模型等,对2006-2020年各城市的高质量发展水平进行了动态测度、系统差异比较、空间关联分析、发展趋势预测。主要结论如下:(1)陕北重点生态功能区的发展水平均值高于关中重点开发区、陕南重点生态功能区,城市间异质性明显。(2)关中重点开发区的人口、经济、社会强于两个重点生态功能区,生态弱于两个重点生态功能区。(3)各城市对其他城市的空间作用强度总和与高质量发展水平有较高的拟合度,高质量发展在区域间具有带动作用。(4)预计2021-2025年,除个别城市,重点生态功能区与重点开发区的高质量发展水平分别呈上升、下降趋势,但幅度均较小。基于高质量发展水平实际状态和未来趋势,区域间的联动、互助应更加灵活,探索形成高质量发展区支援低质量发展区的路径。